MST1 (Mammalian STE20-like protein kinase 1, STK4, KRS2) is a kinase that phosphorylates histone H2B at serine 14 during apoptosis and in response to double-strand DNA breakage. Amino acids 2-488 of MST1 (accession number NP_006273.1) were expressed with an N-terminal GST-tag, (MW=82 kDa) in Sf9 cells using a baculovirus expression system.
